Novel Extraction Material Based On Metal-Organic Framework And Its Application In Exhaled Breath Analysis

Currently, lung cancer is one of the most common cancers, and the mortality burden is high. In recent years, many researchers have devoted to search of method for the early diagnosis of lung cancer. Early diagnosis of lung cancer may help to reduce mortality in lung cancer patients and prolong their survival time. Breath analysis is a new non-invasive diagnostic method. Because the concentration of lung cancer biomarker in exhaled breath is very low and the matrix is relatively complex. Therefore, an effective preconcentration of target analytes is required, to improve accuracy and sensitivity of the analysis.Solid phase microextraction (SPME) is an attractive pretreatment method, it has many advantages such as simple operation, fast analysis, solvent free or less solvent, environmental pollution and good reproducibility. At the same time, solid phase microextraction can combine with separation system, such as high performance liquid chromatography and gas chromatography-mass spectrometry analysis. However, it has some disadvantages, for example, the limited kinds of commercial adsorbent materials, the smaller extraction capacity, fragility of fused silica substrates and so on.Metal-organic frameworks (MOFs) are a new class of porous materials from metal ions or metal ion clusters and organic ligands. MOFs have great potential of being selective adsorbents for preconcentrators due to their high surface areas, tailorable molecular properties and uniform structured. Recently, research on the application of MOF material in the field of separation attracted more and more attention of researchers.Therefore, new solid phase miroextraction methods were developed based on the materials, and they were combined with high performance liquid chromatography (HPLC) and gas chromatography mass spectrometry (GC-MS) for the determination of low molecular weight volatile organic compounds in human exhaled breath. The main research contents of this paper are as follows:1. High quality MOF-199films were in situ grown by hydrothermal synthesis on a stainless steel mesh as extraction phase of thin-film solid phase microextraction, aldehydes (C4-C9) in exhaled breath condensates of lung cancer patients and healthy volunteers were measured by coupling the extraction method with HPLC. In the method, derivatization, extraction and desorption conditions were optimized. Under the optimum conditions, satisfactory results were gained, a wide linear application range was obtained in the range of0.002-8.0μmol L-1(R＞0.995) for six aldehydes, the limits of detection ranged from1.3to20.3nmol L-1. Reasonable recoveries were obtained in the range of74%-120%. The relative standard deviations of intraday and interday were below14.7%and12.6%, respectively. The results show that the developed method is simple, rapid, sensitive and efficient.2. Metal-organic framework199/polydimethylsiloxane hybrid composites coated stainless steel fiber was successfully prepared and used as new extraction absorbent of solid phase microextraction, a SPME-GC-MS method was developed. It was successfully used for the determination of volatile metabolic small molecule compounds in exhaled breath samples of lung cancer patients and healthy people. Experimental conditions that influence efficiency of extraction and desorption were optimized. Under the optimum conditions, the good linear correlation coefficient (r) of0.9906-0.9999were obtained, the detection limits ranged from0.2ng L-1to5.5ng L-1, the satisfactory recoveries were in the range of77%-115%. The method was suitable for analysis of VOCs in complex biological samples.